An object region extraction system is used for finding an object region in three-dimensional space which becomes a key for estimating where on a map the object exists. An example of such an object region extraction system is described in Patent Document 1.
An image processing system described in Patent Document 1 comprises: a region extraction unit which, from a first to an n-th images (n: integer equal to or larger than two) obtained by capturing a real space, extracts a first to an n-th regions within the respective images each indicating an object in three-dimensional space; a coordinate transformation unit which, using first to n-th coordinate transformation information for transforming the above-mentioned first to n-th images into a specified planar coordinate system in the above-mentioned real space, transforms the first to n-th regions into respective regions in the above-mentioned planar coordinate system; an overlap detection unit which detects an overlap between a plurality of regions in the above-mentioned planar coordinate system obtained by the above-mentioned coordinate transformation unit; and a determination unit which determines, on the basis of the detection result by the above-mentioned overlap detection unit, existence of an object region in three-dimensional space in a specified plane within the above-mentioned real space.